Elapsed TimeCalculator
Measure elapsed duration however suits you: a live stopwatch and timer with laps, precise to the millisecond, or a calculator for the elapsed time between two times or two dates — everything runs in your browser, in hours, minutes and seconds.
Stopwatch Timer
Press Start to begin measuring elapsed time precisely.
Calculate Elapsed Time Between Two Times
Set a start and an end time to get the elapsed time between them.
Start Time
End Time
Overnight Calculation
Calculate Elapsed Time
Elapsed Time Result
Calculate Elapsed Time Between Two Dates and Times
Measure the exact duration between two dates and times, to the second.
Start Date and Time
End Date and Time
Calculate Duration
Detailed Duration Result
See How Elapsed Time Is Calculated
A live visual of the elapsed time from start to finish.
Interactive Start-to-End Timeline
The timeline redraws whenever you change the start or end in the calculator above.
Elapsed Time Calculation Examples
Tap an example to populate the calculator with its times.
Example: 9:00 AM to 5:00 PM
End − Start: 5:00 PM − 9:00 AM gives 8 hours, 0 minutes, a standard working day — 8.00 in decimal hours.
Example: 8:30 AM to 4:45 PM
End − Start: 4:45 PM − 8:30 AM gives 8 hours, 15 minutes, or 8.25 decimal hours, because 15 ÷ 60 = 0.25.
Example: 10:00 PM to 6:00 AM
An overnight calculation, since the end is on the next day. Add 24 to the end hour: (6 + 24) − 22 = 8 hours, or 8.00 decimal.
Example: 1:15 PM to 2:05 PM
End − Start: 2:05 PM − 1:15 PM gives 0 hours, 50 minutes — about 0.83 decimal hours (50 ÷ 60). Ideal for logging short meetings.
Quick Elapsed Time Calculator Examples
Tap a card to populate the elapsed time calculator straight away.
How to Calculate Elapsed Time
Methods for calculating elapsed time by hand, step by step.
Elapsed Time Formula
Everything rests on one formula:
Same-Day Calculation
If both times are on the same day, subtract directly. For 9:00 AM to 5:00 PM:
In 24-hour time: 17:00 − 09:00 = 8 hours, 0 minutes.
In minutes: (17 × 60 + 0) − (9 × 60 + 0) = 1020 − 540 = 480 minutes, which is 8 hours.
Calculation When Minutes Require Borrowing
If the end minutes are smaller than the start minutes, borrow one hour (60 minutes). For 8:45 AM to 2:20 PM:
Overnight Calculation
If the span passes midnight, the end belongs to the next day, so add 24 hours to it before subtracting. For 10:00 PM to 6:00 AM:
Convert Elapsed Time to Decimal Hours
Writing elapsed time as one decimal number for timesheets and payroll.
Hours and Minutes to Decimal Hours
Divide the minutes by 60 and add the result to the hours. You end up with one number that multiplies cleanly by an hourly rate.
Decimal Hours Formula
45 Minutes to Decimal Hours
45 ÷ 60 = 0.75, so 2 hours 45 minutes is 2.75 decimal hours. At $25 an hour that is 2.75 × $25 = $68.75.
15 Minutes to Decimal Hours
15 ÷ 60 = 0.25, so 3 hours 15 minutes is 3.25 decimal hours. The quarter-hour steps are 15 min = 0.25, 30 min = 0.50 and 45 min = 0.75.
Elapsed Time in Different Formats
One duration shown in every common format together.
Change the duration to see every format update:
2 hours, 45 minutes
Hours and Minutes2.75
Decimal Hours165
Total Minutes9900
Total SecondsElapsed Time for Work Shifts
Practical elapsed time examples for typical work schedules.
Regular Workday
A 9:00 AM to 5:00 PM shift lasts 8 hours (8.00 decimal). Take off a 30-minute lunch and the net time is 7 hours 30 minutes (7.50); with a one-hour lunch it is 7 hours (7.00).
Overnight Shift
A nurse on 7:00 PM to 7:00 AM works 12 hours (12.00 decimal), and a factory night shift from 10:00 PM to 6:30 AM is 8 hours 30 minutes (8.50). Use the overnight option whenever a shift crosses midnight.
Decimal Hours for Timesheets
Payroll usually asks for decimal hours: 15 min = 0.25, 30 min = 0.50, 45 min = 0.75. A shift of 8 hours 45 minutes goes on the timesheet as 8.75 — not 8.45, which would mean 8 hours and 27 minutes.
| Shift | Elapsed | Decimal |
|---|---|---|
| 9:00 AM → 5:00 PM | 8h 0m | 8.00 |
| 7:30 AM → 4:00 PM | 8h 30m | 8.50 |
| 8:00 AM → 4:45 PM | 8h 45m | 8.75 |
| 10:00 PM → 6:30 AM 🌙 | 8h 30m | 8.50 |
| 7:00 PM → 7:00 AM 🌙 | 12h 0m | 12.00 |
Common Elapsed Time Calculation Mistakes
Frequent errors to watch for when working out elapsed time.
Forgetting About Midnight
From 10:00 PM to 6:00 AM, plain subtraction gives −4 hours. Add 24 first: (6 + 24) − 22 = 8 hours. Always check whether the span crosses midnight.
Confusing Decimal Hours With Hours and Minutes
8.50 decimal hours ≠ 8 hours 50 minutes. The .50 is half an hour, so 8.50 is 8 hours 30 minutes, and 8.75 is 8 hours 45 minutes — never "8:75".
Mixing AM and PM
Typing 5:00 AM instead of 5:00 PM shifts the answer by 12 hours. Check the AM/PM setting before calculating; the inputs show it clearly to help.
Forgetting the End Date
Monday 3:00 PM to Tuesday 3:00 PM is 24 hours, not zero. When the span covers more than one day, use the date-and-time section above so the dates are included.
Incorrectly Subtracting Minutes
2:15 to 4:05 is not 4:05 − 2:15 = 1:90. Borrow an hour: 3 hours 65 minutes − 2 hours 15 minutes = 1 hour 50 minutes. In minutes: 245 − 135 = 110 = 1h 50m.
Elapsed Time Formula Reference
Short formula cards for each kind of elapsed time sum.
Basic Formula
Same day: put both times in 24-hour form and subtract.
Overnight Formula
Crossing midnight: add 24 hours to the end time, then subtract.
Decimal-Hour Formula
Turn h:m into a decimal: 7h 45m → 7 + 0.75 = 7.75.
Total-Minutes Formula
Turn h:m into minutes: 3h 15m → 195 minutes.
How the Elapsed Time Calculator Works
Time any activity with stopwatch precision.
Press Start
Tap Start and the display counts up in hours, minutes, seconds and milliseconds right away.
Record Laps
Press Lap while it runs to capture a split, with the individual lap duration and the running total.
Stop Timer
Press Stop to freeze the count. You can resume with Start or reset to zero.
Read Results
The summary gives total hours, minutes, seconds and decimal hours, and the lap table stays until you reset.
What Is an Elapsed Time Calculator?
What elapsed time measurement is and where it helps.
Precision time tracking
An Elapsed Time Calculator is a digital stopwatch: it measures how long passes between pressing Start and pressing Stop, with a live readout for work sessions, workouts, cooking or any other activity.
A wall clock tells you the time of day; an elapsed timer measures relative duration — how long something has been going on.
High-resolution timing
The stopwatch uses the browser's performance.now() clock, which is precise to fractions of a millisecond. Because each reading is calculated from the start timestamp instead of by counting intervals, it stays correct while the tab sits in the background.
Lap splits for detailed analysis
The lap feature divides a session into parts, recording each segment's own length plus the cumulative total — perfect for runners' splits, process benchmarks or comparing a series of tasks.
When to Use an Elapsed Time Calculator
Where a precision timer makes a real difference.
Running & Fitness
Capture lap splits in interval sessions, time sets in the gym, or log full marathon training runs mile by mile.
Development & Debugging
Time build processes, API calls or deployment pipelines, and compare runs before and after an optimisation.
Client Billing
Start the timer when a call or task begins to capture billable hours, then put the decimal hours on the invoice.
Lab & Experiments
Time chemical reactions, incubations and experiment stages, marking phase transitions with laps.
Presentations & Speeches
Rehearse a talk, track total speaking time and lap each section to keep it within the allotted time.
Cooking & Baking
Time proofing dough, marinades and multi-stage recipes while keeping an eye on total elapsed cooking time.
Elapsed Time Calculator FAQ
Answers to common questions about the Elapsed Time Calculator.
It reads your browser's high-resolution clock (performance.now()), which is precise to well under a millisecond, and refreshes the display about every 10 milliseconds so the count looks smooth.
Yes. Press "Lap" while the stopwatch runs to capture a split. Each lap shows its own length and the running total, and there is no limit on the number of laps.
Yes. Elapsed time is worked out from the moment you pressed Start rather than by counting ticks, so the reading is correct again as soon as you come back to the tab.
Yes. Start the stopwatch when work begins, add a lap at each change of task and stop at the end. The total in decimal hours is ready for time-based billing.
There is no practical limit — it can run for days or weeks without drifting, and the hours display simply grows past 99.
No. Everything runs in your browser; nothing is uploaded and nothing survives a page reload. Use the Copy button or note your times before leaving.
Go to "Calculate Elapsed Time Between Two Times", enter the start and end, tick the overnight box if the end is on the next day, and press Calculate. The answer appears in several formats at once.
When the end time is earlier than the start because the span crosses midnight, tick "End time is on the next day". 24 hours are then added to the end time before subtracting, which gives the correct overnight duration.